LAS VEGAS (USATODAY.com) - What might have been the most attended and loudest weigh-in in the history of boxing ended Friday with Floyd Mayweather and Saul "Canelo" Alvarez both making weight for their super welterweight championship fight.

Saturday night's main event at the MGM Grand Garden Arena is expected to be the most lucrative fight the sport has ever seen.

The 12,200 people in attendance, most of them Mexican fans supporting Alvarez, who hails from Guadalajara, were the beneficiaries of an arena first. The MGM opened the full arena for a weigh-in for the first time, and 90 minutes before the event, fans were being turned away.

There was buzz among the news media the last couple of days that Alvarez might be over the limit for the fight, which will be contested at a catchweight of 152 pounds. That 2-pound drop caused hard feelings between the camps, as Alvarez revealed Tuesday that his team was forced to drop the weight by the Mayweather team. Mayweather Promotions CEO Leonard Ellerbe said the champion was taking advantage of his standing as an "A-side" fighter.

"I was born ready," Alvarez, 23, said when asked the question after his weigh-in. The redheaded fighter weighed in at exactly 152 pounds, prompting a major cheer from his fans and undoubtedly sighs of relief. Mayweather came in at 150.5 pounds.

When Mayweather offered Alvarez his WBC title belt, Alvarez refused to take it, still apparently a little steamed over the catchweight incident.

Golden Boy CEO Richard Schaefer, standing right behind the fighters when they stared one another down after the weigh-in, said Alvarez was feisty with one of the sport's great trash-talkers.

"I'm not going to let that guy tell me what to do," Alvarez said. "(Bleep) him."

The oddest weigh-in involved junior welterweight titlist Danny "Swift" Garcia, who will meet Argentine Lucas Matthysse in a 12-round title fight on the main undercard bout.

When Garcia stepped on the scale and it was announced he was a half pound over the 140-pound weight limit, he had a puzzled look on his face. Generally fighters get an hour to try to lose the weight, but Garcia asked for an immediate re-weigh. This time he came in at exactly 140 pounds.

"I had weighed in earlier at 140," Garcia said, "and I think all the people (hovering) around the scale might have affected it."

Matthysse also came in at 140 pounds.

Fans began lining up early Friday morning for a chance to see some of the sport's best, including Mayweather, generally considered the best pound-for-pound fighter in the world. As usual, the man nicknamed "Money," who is a little better than a 5-2 favorite, got the loudest boos.

Mayweather said he will spend the next 24 hours relaxing and watching college football. He is a well-known gambler who bets a lot on college football games.

Billed as "The One," Saturday's historic fight card headlined by Mayweather vs. Alvarez for the unified super welterweight title (Showtime pay-per-view, 9 p.m. ET) is expected to break records. Both boxers were looking forward to the arena being fully opened for the weigh-in.

Usually less than half the arena is open for weigh-ins. But this fight card has been record-setting in many ways, including the largest live gate at more than $20 million, and promoters are hoping for the largest pay-per-view buy rate in boxing history. The record is held by the Mayweather-Oscar De La Hoya fight at 2.4 million buys in 2007.

Two fights promoted by Golden Boy were unofficially announced before the weigh-in. Marcos Maidana will take on undefeated Adrien Broner in a pay-per-view event on Dec. 14, likely in Las Vegas, and Devon Alexander and Amir Khan will fight Dec. 7, likely at the Barclays Center in Brooklyn. All four fighters attended the weigh-in. No contracts have been signed.